US 3550831 A
Description (OCR text may contain errors)
United States Patent 7/1966 Maynard......................
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ABSTRACT: A tool for driving successive nails from a strip includes a nosepiece structure forming a drive track to which nails are fed in sequence from a guideway extending to a magazine. The strip is indexed through the guideway by a pawl assembly actuated by placing the tool against a workpiece. The pawl assembly includes a plate which has a toothed nail engaging portion and which is mounted for pivoting movement toward and away from the guideway and rectilinear movement toward and away from the guide track. An actuator reciprocated in a vertical direction by a spring and selective engagement with the workpiece carries a pin sliding in an inclined slot in the pawl plate to actuate the pawl assembly.
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PATENTEU UEC29 I976 SHEET 3 BF 3 e lnven/ar ALLEN R. OBERGFELL Attorneys.
MECHANICAL FASTENER FEEDING ASSEMBLY BACKGROUND OF THE INVENTION This invention relates to a fastener feeding assembly and, more particularly, to'a new and improved assembly actuated by placing the tool against a workpiece for feeding successive fasteners from a strip into the drive track of the tool.
Pneumatic tools for driving fasteners from strips, either flexible or relatively rigid, have used various fastener feeding assemblies with pawls, followers, or sprockets for advancing successive nails or fasteners into a drive tracli in synchronism with the operation of the fastener driving tool. These feeding assemblies have been resiliently, pneumatically, ormechanically operated. As an example, U.S. Pat. No. 3,259,292 discloses a mechanically actuated nail feeding apparatus using a sprocket wheel indexed through successive steps by means of a drive pin rotated by placing the nosepiece of the tool on a workpiece. This type of drive subjects the drive pin to rather substantial torsional stresses in dependence on the manner in which the tool is used. Accordingly, it would be desirable to provide a mechanically actuated feeding assembly using easily manufactured and replaced parts of a durable construction.
SUMMARY OF THE INVENTiON- A mechanically actuated fastener feeding assembly for use with a pneumatically actuated fastener driving too] and embodying the present invention includes the housing for the tool and a nosepiece structure both defining a drive-track and having a lower end adapted to be placed adjacent the workpiece into which the fastener or nail is to be driven. The nosepiece structure also includes a projecting structure defining a portion of a guideway opening into the drive track, and the fastener feeding assembly is mounted on the nosepiece struc: ture to complete the definition of the guideway. A platelike pawl mounted in a recessed wall of the assembly includes a toothed nail shank engaging portion offset from the plane of the pawl and extending through an elongated opening into the guideway. The pawl is mounted in the recess for rectilinear movement toward and away from the drive track and pivoting movement toward and away from the guideway with a spring normally biasing the toothed portion of the pawl into engagement with the shanks of the nails in a strip disposed in the guideway. The pawl assembly is actuated by an assembly including a generally flat plate mounted for reciprocating movement generally parallel to the pawl and having a portion surrounding and projecting below the lower end of the nosepiece structure. A pin carried on the actuator plate is slidably received within an inclined slot formed in the pawl.
When the tool is positioned against a workpiece, the actuator moves vertically and elevates the pin which cooperates with the slot in the pawl to retract or slide the pawl in a direction away from the workpiece. During this movement, the pawl is pivoted against the spring to move the toothed portion out of engagement with one set of nails and then back into engagement with a new set of nails to prepare the strip for being advanced to feed the next nail into the drive track. After the tool has been operated to drive the nailthen in the drive track and the tool is lifted from engagement with the work- BRIEF DESCRIPTION OF THE DRAWINGS Many other objects and advantages of the present invention will become apparent from considering the following detailed description in conjunction with the drawings in which:
FIG. 1 is an elevational view of a mechanically actuated nail feeding assembly embodying the present invention;
FIG. 2 is an enlarged sectional view taken .along line 2-2 in FIG. 1;
FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;
FIG. 4 is a fragmentary sectional view taken along line 4-4 in FIG. 3;
FIG. 5 is a sectional view taken along line 5-5 in FIG. 3;
FIG. 6 is a sectional view taken along line 6-6 in FIG. 2;
FIG. 7 is an exploded perspective view of a nosepiece structure for a fastener driving tool and the components of the fastener feeding assembly; and
FIG. 8 is an exploded perspective viewof a pawl and pawl supporting member included in the fastener feeding assembly and illustrated from the opposite side from FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more specifically to the drawings, therein is illustrated a fastener feeding assembly which embodies the present invention and which is indicated generally as 10. The fastener feeding assembly 10 is adapted for use with a pneumatically actuated fastener driving tool and feeds successive headed fasteners such as nails 12 (FIGS. 2 and 3) from a nail strip indicated generally as 14 from a magazine indicated generally as 16 to a drive track 18 formed in a nosepiece structure indicated generally as 20. The nosepiece structure 20 closes and is secured to the lower portion of a housing 22 for the fastener driving tool. Each time that the tool is placed against a workpiece (not shown), the assembly 10 is actuated to feed a nail 12 from the strip 14 to the drive track 18.
Although the nail strip 14, the magazine assembly 16, and the fastener driving tool can be of any suitable construction, the illustrated nail strip 14 including a generally U-shaped plastic carrier 24 for holding the nails 12 in spaced parallel relation is one illustrated and described in detail in the copending application of George .I. Gallee et al., Ser. No. 637,510, filed may 10, 1967, now Pat. No. 3,438,487. The magazine assembly 16 can be of any suitable type, such as the one shown and described in detail in the copending application of Allen R. Obergfell et al., Ser. No. 736,425, filed June 12, 1968, which application is also assigned to the same assignee as the present application. The pneumatic fastener driving tool of which the housing 22 forms a part can also be of any suitable construction such as that shown in the cope nding application of Allen R. Obergfell, Ser. No. 767,020, filed Aug. 26, 1968, abandoned, which application is assigned to the same assignee as the present application.
Referring now more specifically to the nosepiece structure 20, this structure includes a forward portion 20A defining the drive track 18 and terminating in agenerally cylindrical portion 208 at its lower end forming thelow er end of the drive track 18. The rearwardly extending portion of the part 20A of the nosepiece structure 20 includes a slot 26 (FIG. 7) forming an access opening to the drive track 18 that opens to the rear of the tool. The nosepiece structure 20 also includes a rearwardly extending wall portion 20C (FIG. 7) which defines one half of a guideway for feeding the strip '14 from the magazine assembly 16 to the drive track 18, which guideway is indicated generally as 28. As illustrated in FIG. 3, the rearwardly extending wall portion 20C includes a recess 30 for accommodating the U-shaped flexible carrier 24 and another recess 32.
The definition of the guideway 28 is completed by a pair of wall members 34 and 36 (FIGS. 3 and 7) which are disposed in generally parallel relationship with respect to each other with the right-hand portion of the wall member 34 (FIG. 3) disposed in an adjacent relation to the wall portion 20C of the nosepiece structure 20 to completethe definition of the guideway 28. The wall members 34 and. 36 are secured together in an abutting relation by a pair of threaded fasteners .or machine screws 38, and the wall member 36 is secured to as 42 is secured to the nosepiece structure 20 as by a plurality.
of threaded fasteners 44 (FIGS. 1, 2, and 5) to provide a continuation of the guideway 28 for guiding the spent portion of the nail strip carrier 24 forwardly of the drive track 18 after the nails 12 have been removed therefrom and driven into a workpiece.
To provide means for feeding the nail strip 14, the assembly includes a pawl indicated generally as 50 having a central and generally vertically extending flat wall portion 50A (FIG. 7), a rounded or arcuate lower end portion 508, and an offset or transversely extending toothed portion 50C at its upper end. The pawl 50 is mounted in a recess 52 formed in an outer surface of the wall member 34 with the toothed portion 50C extending through an elongated opening 54 in the wall 34 (FIGS. 7 and 8) to be coupled with the shanks of the nails 12. The arcuate or rounded portion 503 of the pawl 50 is slidably and pivotally mounted on a surface 34A (FIGS. 3, 5, and 6) of the wall member 34.
To provide means for resiliently biasing the toothed portion 50C of the pawl 50 into a coupled relation with the shanks of the nails 12, there is provided a spring member indicated generally as 56 (FIG. 7) having a coiled portion 56A and an upper arm portion 56B. The spring 56 is mounted on the wall member 34 by an elongated threaded fastener 58 which passes through a bore or opening 60 in the wall member 34 with an intermediate portion of the fastener 58 passing through the coiled portion 56A. When so mounted on the wall member 34, the coiled portion 56A is disposed within a recess or slot 62 in the wall 34 with the transversely extending arm 56B bearing against the vertical wall portion 50A of the pawl member 50in sliding engagement therewith (see FIGS. 2, 3, 5, and 6). The spring 56 pivots the pawl 50 about the lower rounded portion 508 in a clockwise direction (FIG. 3) to force the toothed portion 50C through the opening 54 and into a coupled engagement with the shanks of the nails 12 disposed adjacent the pawl 50 in the guideway 28.
To provide means for operating the pawl 50, an actuating means indicated generally as 66 is provided having an upper flat or plate portion 66A slidably mounted in a recess 68 formed on an inner surface of the wall member 36. The actuating means 66 includes a lower and semicylindrical portion 66B which partially encircles and is normally disposed beneath the cylindrical portion 203 on the nosepiece structure (FIGS. 1, 3, and 5). The actuating member 66 is normally resiliently biased to the position illustrated in FIGS. 1, 3, and 5 by a pair of compression springs 70 which are disposed in a pair of downwardly facing openings 72 in the lower edge of the wall member 36. The upper end of each of the compression springs 70 bears against the endwall defining the upper end of each of the openings 72, and the lower ends of each of the springs 70 bear against a pair of flanges or tabs 66C struck out-of the vertical wall 66A of the actuator 66. The tabs 66C extend through slots 74 formed in the lower edge of the wall member 66 aligned with the openings 72. The actuator 66 is coupled to the pawl 50 by a pin 76 which is secured to the flat wall 66A and is slidably received within a slot 78 formed in the vertical wall portion 50A of the pawl 50, the wall portions 50A and'66A being disposed generally parallel to each other and to the guideway 28 (FIG. 3).
'To prevent retrograde or reverse movement of the strip 14 during operation of the feeding assembly 10, a resilient locking pawl 80 including a toothed portion 80A is disposed in the'opening or recess 32 in the Wall 20C of the nosepiece structure 20 and is secured therein by a pair of fasteners such as a pair of rivets 82 (FIGS. 3, 4, and 7). The toothed portion 80A of the detent or pawl 80 projects into the guideway 28 generally opposite but somewhat below the toothed portion 50C on the pawl 50 to engage the shanks of a set of nails in the strip 14. The toothed portion 80A is so formed that the pawl or'detent 80 is cammed to the right (FIG. 3) when the strip is moved to the left (FIG. 5) but prevents movement of the nail strip 14 to the right (FIG. 5).
When the tool of which the fastener feeding assembly 10 forms a part is to be operated, a pivoted front cover 16B on the magazine assembly 16 is opened and a rolled fastener containing strip 14 is disposed within the magazine 16. The leading edge of the strip 14 is advanced to the position shown in FIG. 2 by feeding the strip through the guideway 28 so that the v first nail 12 in the strip 14 is disposed in the drive track. 18 The cover 16B is then closed, and the tool is prepared operation.
When the tool is to be operated, the workpiece engagi i'igi portion 66B of the actuator is placed against the workpiece. The tool is then depressed so that theactuator 66 moves upwardly against the compressive force of the springs 70. If desired, the actuator 66 can be coupled to a safety or touch-. trip mechanism of the type disclosed in the above-identified Obergfell application which is-cornbined with a trigger control,
to provide an interlock by which the tool cannot be operated unless the lower end of the drive track defining'portion 20B of the nosepiece structure 20 is placed against the workpiece.
When the tool is thus operated or controlled, a driver blade direction of movement of the nails 12, the pin 76 bears against the upper edge of the portion of the flat wall 50A of the pawl 50 defining the slot 78 to cam the pawl 50 to the right from the position shown in solid outline in FIG. 5 to the position shown in dot-and-dash outline in FIG. 5. During this movement, the arcuate lower end portion 50B of the pawl 50 slides along the surface 34A. During this movement, the toothed portion 50C on the pawl cams against the shanks of the nails 12 in the guideway 28 to pivot the pawl 50 about the arcuate portion 503 and against the force of the spring 56 to the position shown in FIG. 6 so as to permit the pawl 50 to move rearwardly away from the drive track 18 to the position shown in dot-and-dash outline in FIG. 5. As the pawl 50 approaches this position and after the separate teeth of the toothed portion 50C move past one set of nails 12, the spring 56 pivots the pawl 50 in a clockwise direction about the rounded portion 508 to a position in which the toothed portion 50C is again coupled with the shanks of a set of nails in the strip 14 in the I the actuator 66. During this movement, the pin 76 cooperates with the lower wall defining the slot 78 on the pawl 70 to impart rectilinear sliding movement toward the drive track 18 from the right-hand position shown in dot-and-dash outline in 7 FIG. 5 to the position shown in solid line therein. During this movement, the pawl 50 advances the strip 14 a single step so that the next nail 12 is now disposed beneath the lower end of the driving element 90 within the drive track 18. The forward end of the carrier 24 from which the nail has been driven is advanced into the guideway structure 42. In this manner, a nail 12 is advanced into the drive track 18 each time that the nosepiece structure 20 of the tool is placed adjacent a workpiece.
Although the pawl 50 is illustrated as engaging the nails 12 to feed the strip 14 toward the drive track, this pawl can engage the carrier 24 to feed the strip 14 by merely placing the feeding assembly on the opposite side of the guideway 28.
1. In a tool for driving fasteners into a workpiece from a strip of spaced fasteners:
structure defining a drive track and having a lower end adapted to be disposed adjacent the workpiece;
a magazine assembly for receiving a strip of fasteners and having a guideway leading into the drive track through which the strip extends;
pawl means mounted for pivoting and reciprocating movement, said pawl means being adapted to engage the fastener strip in said guideway; a workpiece engaging means movably mounted adjacent said lower end and adapted to engage the workpiece; and means coupling the workpiece engaging means to the pawl means so that movement of the workpiece engaging means imparts pivotal and reciprocating movement to the pawl means to feed the fastener strip through said guideway toward the drive track. 2. In a tool for driving a fastener from a strip of spaced fasteners into a workpiece: structure defining a drive track and having a lower end adapted to be disposed adjacent the workpiece, saidstructure also defining a guideway leading into the drive track adapted to receive a strip of fasteners, said structure also forming a recessed area communicating with the guideway;
pawl means disposed in said recessed area and resiliently biased into engagement with a fastener in the guideway, said pawl means being mounted for pivoting movement toward and away from the fastener in the guideway and for reciprocating movement in a direction parallel to the guideway;
movably mounted actuating means adapted to engage the workpiece and including a portion mounted for reciprocating movement in a direction generally parallel to the drive track; and
means coupling the pawl means and said portion of the actuating means to reciprocate the pawl means in response to reciprocation of said portion, the. reciprocation of the pawl means advancing the fastener strip in the guideway and pivoting the pawl means in opposite directions to couple the pawl means to successive ones of the fasteners.
3. In a tool for driving a fastener from astrip of spaced fasteners into a workpiece:
structure defining a drive track and having a lower end adapted to be disposed adjacent the workpiece, said structure also defining a guideway. leading into the drive track adapted to receive astrip of fasteners, said structure also forming a recessed area communicating with the guideway;
a pawl member disposed in transversely extending toothed portion, said pawl member being mounted for pivotal movement toward and away from the guideway and for reciprocating movement parallel to the guideway;
resilient means biasing the toothed portion into engagement with the fastener strip in the guideway;
an actuating assembly operated by engagement with the workpiece and including an actuating member mounted adjacent the pawl member for reciprocating movement in a direction transverse to the direction of movement of the fastener through the guideway; and
coupling means coupling the pawl and actuating members and including a pin on one of the members and an inclined slot in the other of the members for reciprocating the pawl member in response to reciprocation of the actuating member, reciprocation of the pawl member feeding the fasteners toward the drive track and pivoting the toothed portion into and out of coupled relation with the fastener strip. v
4. In a tool for driving fasteners into a workpiece from a strip of spaced fasteners:
structure defining a drive track and a portion of a strip guideway communicating with the drive track;
an assembly mounted on the structure and including a wall member cooperating with the structure to complete the definition of the strip guideway, said wall member providing an elongated opening communicating with the guideway;
pawl means mounted on said wall member for reciprocating said recessed area and having amovement generally parallel to the guideway and toward and away from the drive track, said pawl means having a toothed portion extending through the elongated opening to engage the fastener strip in the guideway; and
actuating means coupled to the pawl'means and actuated by engagement with the workpiece for actuating the pawl means.
5. The tool set forth in claim 4 in which:
the wall member includes a recessed area communicating with the elongated opening and spaced away from the guideway; and
the pawl means includes a generally flat plate portion disposed in the recessed area and having the toothed portion extending into said elongated opening substantially perpendicular to the flat plate portion.
6. The tool set forth in claim 5 in which, the actuating means includes a flat plate portion at least partially closing the recessed area and mounted for rectilinear movement in a direction transverse to the direction of reciprocating movement of the pawl means.
7. The tool set forth in claim 6 in which, the flat plate portion of the actuating means and the pawl means are coupled together by a pin slidable within an inclined slot.
8. The tool set forth in claim 6 in which:
the structure includes a lower and portion adapted to be disposed adjacent the workpiece; and
the actuating means includes a workpiece engaging portion at least partially surrounding the lower end portion and coupled to the flat plate portion of the actuating means.
9. The tool set forth in claim 8 including, resilient means normally biasing the workpiece engaging portion of the actuating means to a position projecting beyond the lower end portion of the structure.
10. In a tool for driving a fastener from a strip of spaced fasteners into a workpiece:
structure defining a drive track and having a lower end adapted to be disposed adjacent. the workpiece, said structure also defining a guideway leading into the drive track adapted to receive a strip of fasteners, said structure also defining an opening extending generally parallel to the guideway and communicating with the guideway through an elongated slot;
a pawl member mounted for sliding and pivoting movement in the opening and including a toothed portion extending through the slot to engage the fastener strip in the guideway;'
first biasing means acting on the pawl member for biasing the toothed portion into coupled'engagement with the fastener strip;
an actuating member disposed adjacent the pawl member;
coupling means including a pin and an inclined slot on the actuating and pawl members for coupling these members;
means actuated by engagement with the workpiece for imparting rectilinear movement in a first direction to the actuating member to move the coupled pawl member in a direction away from the drive track, the pawl member being pivoted out of coupled engagement with the fastener strip and then being pivoted back into engagement with the fastener strip spaced away from the drive track a distance of one fastener by the first biasing means during the movement of the pawl member in said first direction; and second biasing means acting on the actuating member for imparting rectilinear movement to the actuating member in a second direction opposite tothe first direction to move the pawl member in a second direction toward the drive track so that the toothed portion feeds the fasteners toward the drive track. 11. The tool set forth in claim 1 including mounting structure engaging said pawl means to cause reciprocating movement of said pawl means to be substantially rectilinear.